Method of changing a MAC address of a WLAN affiliated STA of a multi-link device

ABSTRACT

A method of changing a MAC address of a WLAN affiliated STA of a multi-link device (MLD) and related system, device and non-transitory machine-readable storage medium. A new MAC address is generated for an affiliated non-AP STA of a non-AP MLD. A request to change the MAC address of the affiliated non-AP STA to the new MAC address is sent from the non-AP MLD to an AP MLD. An acknowledgement that the new MAC address for the affiliated non-AP STA of the non-AP MLD has been successfully applied by the AP MLD is received by the non-AP MLD from the AP MLD. The MAC address for the affiliated non-AP STA of the non-AP MLD is changed to the new MAC address in response to the acknowledgment.

TECHNICAL FIELD

The present disclosure relates to communications, and more specifically,to a method of changing a MAC address of a WLAN affiliated STA of amulti-link device.

BACKGROUND

The Extremely High Throughput (EHT) Task Group (TG) has recently startedstandardization activities within the IEEE 802.11 WLAN project and thisTG is known as IEEE 802.11be. IEEE 802.11be has introduced a multi-linkdevice. A multi-link device (MLD) is a logical wireless local areanetwork (WLAN) entity that has multiple radio links to another MLDentity. A typical use case would be an MLD Access Point (AP) connectingto a non-AP MLD (e.g., a WLAN terminal or handset) using 2 WLAN radiolinks in the 2.4 GHz and 5 GHz WLAN bands. The individual WLAN radiolinks are referred to as links and the radios within the AP MLD arereferred to as affiliated APs. It is intended that each of theaffiliated APs can also serve latency non-AP stations (STAs). Forexample, an AP MLD with a 2.4 GHz radio link could also behave as alegacy AP serving a legacy 802.11ax non-AP STA. In this case, the sourceof the 2.4 GHz radio link is the affiliated AP within the AP MLD. Theradios within the non-AP MLD are referred to as affiliated stations(STAs).

The operation of an MLD is different from that of two logical STAs (amultiband client) in the same physical entity (e.g., two non-AP STAs inthe same handset). Within an MLD the traffic is coordinated between thetwo links and the security association is maintained across them. Thisprovides some benefits over a logical (or virtual) STA. An MLD has morethan one affiliated station and has a single medium access control (MAC)service access point (SAP) to logical link control (LLC), which includesone MAC data service. An MLD may communicate by parallel transmission ona plurality of WLAN radio links between an AP MLD and a non-AP MLD. AnAP MLD is an MLD in which each STA affiliated with the MLD is anaffiliated AP. A non-AP MLD is an MLD in which each STA affiliated withthe MLD is an affiliated STA. An MLD allows traffic to flow on any WLANradio link with the MLD AP and provides a performance gain by using aplurality of channels.

IEEE 802.11 allows a STA to establish a level of privacy for a user(e.g., not be tracked by a third party) by changing its MAC address at aperiodic interval. However, the MAC address of an affiliated STA shouldnot be changed through the lifetime of an association (i.e. when thereis a security association between the non-AP MLD and the AP MLD) orduring a fast transition (FT), thereby limiting privacy for users.

SUMMARY

The present disclosure provides a method of changing a MAC address of aWLAN affiliated STA of a multi-link device and related system, deviceand non-transitory machine-readable storage medium.

An MLD behaves similarly to a legacy STA when connecting to an AP toparticipate in a LAN. To maintain LAN connectivity, a STA MAC addresscan only be changed when the IEEE 802.11 STA is unassociated, in otherwords, when there is no security association between the STA and an AP.The present disclosure provides a method of changing a MAC address of anaffiliated STA of a non-AP MLD, used by the affiliated STA and theaffiliated AP of an AP MLD to which the non-AP MLD is associated,without changing the MAC address used by the AP MLD on a LAN that the APMLD has joined and without affecting LAN connectivity of the AP MLD.This is possible because the MAC address of the affiliated STA is notvisible on the LAN. The MAC address of a non-AP MLD is used on the LANbut is not used to transmit frames over-the-air. An affiliated STA MACaddress is used to transmit frames over-the-air using a specific link.Therefore, the affiliated STA address for a non-AP MLD could changewithout affecting LAN connectivity. Furthermore, as no MLD security isbound to the affiliated STA, the MAC address can be changed withoutaffecting any security bindings. This enables the MAC address of theaffiliated STA to be changed, even though the non-AP MLD is associated.Each of the affiliated STAs of the non-AP MLD may periodically changetheir MAC addresses. Non-AP MLDs can inform the AP MLDs that they have asecurity association with that the MAC addresses of their affiliatedSTAs are about to change. The AP MLDs can respond with anacknowledgement message, which may optionally indicate any errorsituation to the non-AP MLD. Thus, the method of the present disclosureallows user privacy to be maintained for non-AP MLDs through thelifetime of an association and during FT, by changing on a periodicbasis the MAC address used over-the-air for each affiliated STA, withoutaffecting LAN connectivity. Without the method of the presentdisclosure, non-AP MLDs limit privacy of users, through the tracking ofa static MAC address of their affiliated STAs once a securityassociation is made. In accordance some embodiments of the presentdisclosure, an non-AP MLD can request a MAC address change for more thanone affiliated non-AP STA. Conversely, in other embodiments of thepresent disclosure an affiliated non-AP STA can trigger a MAC addresschange request for itself and other affiliated non-AP STAs within acommon non-AP MLD entity, or a MAC address change request of anaffiliated non-AP STA can trigger the non-AP MLD entity to trigger theother affiliated non-AP STAs to request their MAC addresses to change.

In accordance with a first aspect of the present disclosure, there isprovided a method of changing a medium access control (MAC) address of awireless local area network (WLAN) affiliated non-access point station(non-AP STA) of a non-AP multi-link device (MLD), the non-AP MLDcomprising a plurality of affiliated non-AP STAs. A new MAC address isgenerated for an affiliated non-AP STA of a non-AP MLD. A request tochange the MAC address of the affiliated non-AP STA to the new MACaddress is sent from the non-AP MLD to an AP MLD. An acknowledgementthat the new MAC address for the affiliated non-AP STA of the non-AP MLDhas been successfully applied by the AP MLD is received by the non-APMLD from the AP MLD. The MAC address for the affiliated non-AP STA ofthe non-AP MLD is changed to the new MAC address in response to theacknowledgment.

In some or all examples of the first aspect, the method furthercomprises: sending, by the non-AP MLD to the AP MLD, a confirmation thatthe MAC address of the affiliated non-AP STA of the non-AP MLD has beensuccessfully changed.

In some or all examples of the first aspect, the confirmation causes theaffiliated AP of the AP MLD to use the new MAC address mapping for theaffiliated non-AP STA of the non-AP MLD.

In some or all examples of the first aspect, generating the new MACaddress for the non-STA of the non-AP MLD is performed in response todetection of a trigger.

In some or all examples of the first aspect, the trigger is an expiry ofa predetermined amount of time since the MAC address of the affiliatednon-AP STA was set.

In some or all examples of the first aspect, the trigger is a sending ofa predetermined number of frames since the MAC address of the affiliatednon-AP STA was set.

In some or all examples of the first aspect, the predetermined number offrames is 1.

In some or all examples of the first aspect, the method furthercomprises: monitoring for one or more triggers for changing the MACaddress for the affiliated non-AP STA of the non-AP MLD.

In some or all examples of the first aspect, the generating, requestingand changing is performed by the non-AP MLD.

In some or all examples of the first aspect, the generating, requestingand changing is performed by the affiliated non-AP STA of the non-APMLD.

In some or all examples of the first aspect, the monitoring, generatingand changing is performed by the non-AP MLD.

In some or all examples of the first aspect, the monitoring, generatingand changing is performed by the affiliated non-AP STA of the non-APMLD.

In some or all examples of the first aspect, the method furthercomprises: sending data between the affiliated non-AP STA of the non-APMLD and the affiliated AP of the AP MLD using the new MAC address.

In some or all examples of the first aspect, the processing of therequest by the AP MLD causes the AP MLD to apply the new MAC addresschange to a mapping of the affiliated AP of the AP MLD.

In accordance with another aspect of the present disclosure, there isprovided a communication device comprising a processor, a memory and acommunication subsystem. The memory having tangibly stored thereonexecutable instructions for execution by the processor. The executableinstructions, in response to execution by the processor, cause thecommunication device to perform the methods described above and herein.

In accordance with a further aspect of the present disclosure, there isprovided a non-transitory machine-readable storage medium havingtangibly stored thereon executable instructions for execution by aprocessor of a communication device. The executable instructions, inresponse to execution by the processor, cause the communication deviceto perform the methods described above and herein.

Other aspects and features of the present disclosure will becomeapparent to those of ordinary skill in the art upon review of thefollowing description of specific implementations of the application inconjunction with the accompanying figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram illustrating a communications system having an MLDarchitecture in accordance with of the present disclosure.

FIG. 2 is a diagram illustrating an MLD with a non-AP MAC addressarchitecture in accordance with of the present disclosure.

FIG. 3 is a block diagram of an example wireless communication device100 suitable for providing an MLD suitable for practicing the teachingsof the present disclosure.

FIG. 4 is flowchart of a method of changing a MAC address of anaffiliated STA in a non-AP MLD in accordance with a first embodiment ofthe present disclosure.

FIG. 5 is a message sequence diagram illustrating the message flowbetween a non-AP MLD and an AP MLD in accordance with a method ofchanging a MAC address of an affiliated STA in a non-AP MLD of the firstembodiment of the present disclosure.

FIG. 6 is a diagram illustrating a MAC Address Change Notification framein accordance with the present disclosure.

FIG. 7 is a diagram illustrating a MLO Link subfield format inaccordance with of the present disclosure.

FIG. 8 is a diagram illustrating a MAC Address Change Acknowledgementframe in accordance with the present disclosure.

FIG. 9 is a diagram illustrating a MAC Address Change Confirmation framein accordance with the present disclosure.

FIG. 10 is flowchart of a method of changing a MAC address of anaffiliated STA in a non-AP MLD in accordance with a second embodiment ofthe present disclosure.

FIG. 11 is a message sequence diagram illustrating the message flowbetween a non-AP MLD and an AP MLD in accordance with a method ofchanging a MAC address of an affiliated STA in a non-AP MLD of thesecond embodiment of the present disclosure.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

The present disclosure is made with reference to the accompanyingdrawings, in which embodiments are shown. However, many differentembodiments may be used, and thus the description should not beconstrued as limited to the embodiments set forth herein. Rather, theseembodiments are provided so that this application will be thorough andcomplete. Wherever possible, the same reference numbers are used in thedrawings and the following description to refer to the same elements,and prime notation is used to indicate similar elements, operations orsteps in alternative embodiments. Separate boxes or illustratedseparation of functional elements of illustrated systems and devicesdoes not necessarily require physical separation of such functions, ascommunication between such elements may occur by way of messaging,function calls, shared memory space, and so on, without any suchphysical separation. As such, functions need not be implemented inphysically or logically separated platforms, although they areillustrated separately for ease of explanation herein. Different devicesmay have different designs, such that although some devices implementsome functions in fixed function hardware, other devices may implementsuch functions in a programmable processor with code obtained from amachine-readable storage medium. Lastly, elements referred to in thesingular may be plural and vice versa, except where indicated otherwiseeither explicitly or inherently by context.

IEEE 802.11-2020-IEEE Standard for InformationTechnology—Telecommunications and Information Exchange betweenSystems—Local and Metropolitan Area Networks—Specific Requirements—Part11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY)Specifications, dated December 2020, describes privacy and MAC addressissues and states that MAC addresses cannot be changed through thelifetime of an association, the content of IEEE 802.11-2020 beingincorporated herein by reference.

IEEE P802.11be D1.0, dated May 2021, describes state of the artinformation about multi-link devices (MLDs) and multi-link operation(MLO), the content of IEEE P802.11be D1.0 being incorporated herein byreference.

For convenience, the terms messages, frames and message frames may beused in the present disclosure interchangeably.

A multi-link device in the present disclosure may be a single-antennadevice or a multi-antenna device. A multi-link device has one MACaddress that coordinates different radios operating simultaneously. Amulti-link device may have multiple radios that are capable of operatingsimultaneously on different channels in the same or different bands. Thepresent disclosure is not limited to any number of antennas or radios inthe multi-link device. The multi-link device may allow a service of asame access type to be transmitted on different links or even allow asame data packet to be transmitted on different links. Alternatively,services of the same access type cannot be transmitted on differentlinks, however services of different access types can be transmitted ondifferent links.

Referring to FIG. 1 , a communications system 10 having a multi-linkdevice architecture in accordance with the present disclosure will bedescribed. The communications system 10 comprises an AP MLD 12 connectedto a wired local area network (LAN) 30. The AP MLD 12 generates awireless local area network (WLAN) 40 through which it communicates witha non-AP MLD 20, such as a handset. As described above, the non-AP MLD20 supports parallel transmission on a plurality of links, providinghigher transmission efficiency and higher throughput than acommunication device that supports only single-link transmission. The APMLD 12 comprises affiliated APs 14, 16 operating at, for example, 2.4GHz and 5 GHz respectively. The non-AP MLD 20 comprises affiliated STAs24, 26 operating at, for example, 2.4 GHz and 5 GHz respectively. A WLANradio link (referred to as “link” hereinafter) is formed between anaffiliated STA of the non-AP MLD 12 and an affiliated AP of the AP MLD12 (e.g., a link between the affiliated STA 24 and the affiliated AP 14or a link between the affiliated STA 26 and the affiliated AP 16). TheSTAs 24, 26 are logical stations that operate on separate links withinone MLD.

Referring now to FIG. 2 , an MLD with a non-AP MAC address architecturein accordance with the present disclosure will be described. The non-APMLD 20 comprises three logical entities, the non-AP MLD 20 itself andtwo affiliated STAs 24, 26. The affiliated STAs 24 and 26 contain theradios and the non-AP MLD 20 contains parts of the MAC layer and thestation management entity (SME) to the upper layers within the non-APMLD 20. All three entities have a MAC address, denoted MAC_(ML),MAC_(A1) and MAC_(A2), respectively.

A Robust Security Network Association (RSNA) may be established betweenthe AP MLD 12 and the non-AP MLD 20. Each of the links between the APMLD 12 and the non-AP MLD 20 is formed between an affiliated STA of thenon-AP MLD 20 and an affiliated AP of the AP MLD 12. The links,comprising the affiliated STAs 24, 26 of the non-AP MLD 20, aretransparent (invisible) to the MLD RSNA. Although the securityassociations (SA) are handled by the non-AP MLD 20, only the MAC addressMAC_(ML) is used as an identifier for the security associations.Correspondingly from the LAN point of view, the LAN 30 only sees the MACaddress MAC_(ML) at the non-AP MLD 20. The affiliated STA MAC addressesMAC_(A1) and MAC_(A2) are not part of the MLD security associations andare not seen by the LAN 30. When the non-AP MLD 20 connects to the APMLD 12 to communicate in the LAN environment, the MAC address of thenon-AP MLD 20, MAC_(ML), represents the non-AP MLD 20 on the LAN 30.

FIG. 3 is a block diagram of an example wireless communication device100 suitable for providing an MLD for practicing the teachings of thepresent disclosure as either the AP MLD 12 or the non-AP MLD 20. Thewireless communication device 100 includes a processing systemcomprising a processor 104 (such as a microprocessor or centralprocessing unit (CPU)) which controls the overall operation of thewireless communication device 100. The processing system may include oneor more other types of processors coupled to the processor 104, such asa graphic processing unit (GPU), a tensor processing unit (TPU), aneural processing unit (NPU), an application specific integratedcircuit, or a field programmable gate array (FPGA), for offloadingcertain computing tasks. The processor 104 is coupled to a plurality ofcomponents via a communication bus (not shown) which provides acommunication path between the components and the processor 104. Theprocessor 104 is coupled to one or more non-transitory machine-readablestorage media (“memory”) 108, which may include Random Access Memory(RAM), Read Only Memory (ROM), and persistent (non-volatile) memory suchas flash memory, and a communication subsystem 110.

The communication subsystem 110 may comprise a baseband processor orother circuits for implementing a Medium Access Controller, a Physicallayer, transmitting amplifiers, and RF antennas as required forcommunicating over a wireless medium. The communication subsystem 110typically includes at least two stations (STAs) for exchanging radiofrequency signals with the wireless local area network 40 in parallel inaccordance with IEEE 802.11be. IEEE 802.11be also allows one STA to beincluded in the communication subsystem 110. The communication subsystem110 may include more than two STAs in some embodiments. The STAscomprise wireless transceivers. The communication subsystem 110 may alsoinclude a wireline transceiver for wireline communications with wirednetworks such as the wired LAN 30. The communication subsystem 110 mayalso include one or a combination of a Bluetooth transceiver or othershort-range wireless transceiver or a wireless wide area network (WWAN)transceiver such as a cellular transceiver for communicating with aradio access network (e.g., cellular network). The cellular transceivermay communicate with any one of a plurality of fixed transceiver basestations of the cellular network within its geographic coverage area.

The memory 108 stores a variety of instructions executable by theprocessing system and data, some of which may take the form ofapplication programs executable by the processing system. Executableinstructions and data, which may be in the form of system software,software modules, specific device applications, or parts thereof, may betemporarily loaded into RAM during execution. Communication signalsreceived by the wireless communication device 100 may also be stored inRAM. Although specific functions are described for various types ofmemory, this is merely one embodiment, and a different assignment offunctions to types of memory may be used in other embodiments.

The wireless communication device 100 may comprise an internal powersupply such as a battery (not shown) as a power source, depending on thetype of the wireless communication device 100. For example, the wirelesscommunication device 100 may comprise one or more rechargeable batteriesthat may be charged, for example, through charging circuitry coupled toa battery interface such as a serial data port. The battery provideselectrical power to at least some of the components of the wirelesscommunication device 100, and the battery interface (not shown) providesa mechanical and electrical connection for the battery. Alternatively,the wireless communication device 100 may comprise an external powersupply.

Referring now to FIGS. 4 and 5 , a method 400 of changing a MAC addressin accordance with a first embodiment of the present disclosure will bedescribed. FIG. 4 is flowchart of the method 400 in accordance with thefirst embodiment of the present disclosure. FIG. 5 is a message sequencediagram illustrating message flow in accordance with the firstembodiment of the present disclosure. The solid lines in FIG. 5represent over-the-air (OTA) messages whereas the broken lines in FIG. 5present internal messages with an MLD. The frames (messages) sentbetween MLDs can be sent over any link. The method 400 is performed bythe non-AP MLD 20 and the AP MLD 12. At least parts of the method 400may be carried out by software executed by the non-AP MLD 20 and the APMLD 12, by the processors 104 and/or communication subsystems 110thereof.

At operation 402, the non-AP MLD 20 monitors for a trigger to change theMAC addresses of one or more of the affiliated STAs 24, 26 from one ormore predetermined triggers. The triggers may be time-based orevent-based. For example, when the trigger is time-based, the triggermay be the expiry of a predetermined amount of time since the MACaddress of the affiliated STA was set, such as a predetermined periodicinterval. The expiry of the predetermined amount of time may bemonitored by a timer, such as a countdown timer. The predeterminedamount of time may be a few minutes or as a little as a few seconds. Thepredetermined amount of time may be configured based on a privacysetting for the non-AP MLD 20. For another example, when the trigger isevent-based, the trigger may be the sending of a predetermined number offrames since the MAC address of the affiliated STA was set. Thepredetermined number of frames may be as little as a one frame, so thatthe MAC address of the non-AP MLD 20 changes every frame. The smallerthe time-based or event-based interval between changes in the MACaddress, the greater the privacy afforded.

At operation 404, the non-AP MLD 20 detects a trigger from the one ormore predetermined triggers.

At operation 406, the non-AP MLD 20 generates new MAC addresses for oneor more of the affiliated STAs 24, 26 in response to the detection ofthe trigger. There may be situations where not all the MAC addresses ofall the affiliated STAs are changed or changed at the same time.

At operation 408, the non-AP MLD 20 notifies the AP MLD 12 of the newMAC addresses for the affiliated STAs 24, 26, for example, by sending aMAC Address Change Notification frame. An example of a MAC AddressChange Notification frame is described below in connection with FIGS. 6and 7 . The MAC Address Change Notification frame is denoted in themessage sequence diagram (FIG. 5 ) as MAC-ADDR-Change-Notif (MLO Link(Link ID, newMACAddr)₁, MLO Link (Link ID, newMACAddr)_(n)) for 1 . . .n, where n is the number of affiliated STAs of the non-AP MLD 20requesting a change of MAC address, the Link ID is the identifier of thelink of each affiliated STA, and newMACAddr is the proposed new MACaddress.

At operation 410, the AP MLD 12 receives the MAC Address ChangeNotification frame from the non-AP MLD 20 and forwards the MAC addresschange to the affiliated APs 14, 16, instructing them to update theirmapping of the affiliated STAs 24, 26 MAC addresses. In some situations,the AP MLD 12 may not forward the MAC address change to the affiliatedAPs, if it determines that a MAC address change is not appropriate. Theforwarding of the MAC address change comprises sending a MAC AddressChange frame from the AP MLD 12 to the affiliated APs 14, 16. The MACAddress Change frame is denoted in the message sequence diagram (FIG. 5) as MAC-ADDR-Change (newMACAddr), where newMACAddr is the new MACaddress. The MAC Address Change frame instructs the affiliated APs 14,16 to update their mapping of the MAC addresses for the affiliated STAs24, 26. The applying of the MAC address change further comprises theaffiliated APs 14, 16 notifying the AP MLD 12 when their link mapping ofthe MAC addresses for the affiliated STAs 24, 26 have been successfullychanged, for example, by sending a MAC Address Change Acknowledgementframe. For example, the AP MLD 12 may respond to the non-AP MLD 20 witha status of SUCCESS, or may respond with an alternative status ratherthan SUCCESS, such as FAIL, when the requested MAC address changes forthe affiliated STAs 24, 26 have not been applied. The MAC address changemay not succeed for several reasons, for example, if the proposed MACaddress is not suitable to the AP MLD 12 or the affiliated APs 14, 16for some reason (e.g., already in use for another device). Thealternative status may cause the non-AP MLD 20 to re-try the MAC addresschange, in which case operations proceed to operation 406. The MACAddress Change Acknowledgement frame is denoted in the message sequencediagram (FIG. 5 ) as MAC-ADDR-Change-ACK (Status), where Status is thestatus of the MAC address change, either SUCCESS or FAIL. The decisionto update the link mapping of the affiliated STAs MAC addresses can bemade by either the AP MLD 12 or one or more of the affiliated APs 14,16.

At operation 412, the AP MLD 12 notifies the non-AP MLD 120 that thelink mapping of the MAC address for the affiliated STA 24, 26 has beensuccessfully changed by the affiliated APs 14, 16 of the of AP MLD 20,for example, by sending a MAC address Change Acknowledgement frame tonon-AP MLD 20 notifying it that the MAC address has been applied andacknowledged by the AP MLD 12.

It will be appreciated that the AP MLD 12 may respond with a Status codestopping the MAC address change or information about how the MAC addresschange should be performed (e.g., provide information about the localaddress administration). With respect to a Status code stopping the MACaddress, the MAC Address Change Acknowledgement frame can contain astatus other than SUCCESS. If a status other than SUCCESS (e.g., FAIL),then the non-AP MLD 20 can attempt to determine a new address. This canoccur if the AP MLD 12 detects a duplicate MAC address either on the LAN30 or in another affiliated AP. It can also detect that the MAC addressis invalid, e.g. a broadcast address. In some situations, for example inthe case of an enterprise, the MAC addresses may have to fall within acertain address range and this may be a reason to refuse the address.Alternatively, the Status code may be a Status code about using a localaddress administration such as, for example,DENIED_LOCAL_MAC_ADDRESS_POLICY_VIOLATION. In the current standard, anAP has the ability to advertise a MAC address policy and can reject anassociation when the STA uses a MAC address that does not conform to thepolicy. With respect to information about how the MAC address changeshould be performed, an optional subfield such as, for example, localadmin information of variable length, may be added to the MAC AddressChange Acknowledgement frame (FIG. 8 ) to indicate information about thelocal address administration. In this case, the MAC Address ChangeAcknowledgement frame (FIG. 8 ) would require a leading “length”subfield so that the received frame can be correctly parsed.

At operation 414, the non-AP MLD 20 applies the MAC address change tothe affiliated STAs 24, 26 in response to receiving the MAC AddressChange Acknowledgement frame. The applying of the MAC address changecomprises sending a MAC Address Change frame from the non-AP MLD 20 tothe affiliated STAs 24, 26. This MAC Address Change frame instructs theaffiliated STAs 24, 26 to update their MAC addresses affiliated STA. Theapplying of the MAC address change further comprises the affiliated STAs24, 26 notifying the non-AP MLD 20 when their MAC addresses affiliatedSTA have been successfully changed, for example, by sending a MACAddress Change Acknowledgement frame. In some situations, the MACaddress change may not be successful, and this is indicated by thestatus FAIL (or an alternative) within the MAC Address ChangeAcknowledgement frame. The non-AP MLD 20 has now completed the update ofthe link mapping.

At operation 416, the non-AP MLD 20 optionally notifies the AP MLD 12that the MAC address for the affiliated STAs have been successfullychanged, for example, by sending a MAC address Change Confirm frame tothe AP MLD 12. The MAC Address Change Confirm frame is denoted in themessage sequence diagram (FIG. 5 ) as MAC-ADDR-Change-Confirm (Status),where Status is the status of the MAC address change, either SUCCESS orFAIL. The MAC address Change Confirm frame may be used to complete theMAC address change and trigger the use of the new MAC addresses by theAP MLD 12 and non-AP MLD 20. The existing MAC addresses may continue tobe used by the AP MLD 12 and the non-AP MLD 20 to allow MLD trafficflow, while the message sequence in FIG. 5 . is being executed. Once themessage sequence is complete, the new MAC addresses will be used.Therefore all entities within the MLD may store both an existing MACaddress and the new MAC address until signaled to switch over.

FIG. 6 is a diagram illustrating a MAC Address Change Notification framein accordance with the present disclosure. The MAC Address ChangeNotification frame is sent from the non-AP MLD 20 to the AP MLD 12 toindicate that the MAC address of an affiliated STA has requested achange. The MAC Address Change Notification frame may be an actionframe, a protected action frame or an Extensible Authentication Protocol(EAP) over LAN (EAPoL) data frame similar to a Tunneled Direct LinkSetup (TDLS) setup frame. Alternatively, the MAC address change may beperformed over a TDLS link with the same messaging. It will beappreciated by persons skilled in the art that TDLS is a directconnection between two non-AP MLDs 20 that are associated with the sameAP MLD 12. TDLS communications pass directly between the TDLS peers anddo not traverse the AP. The key derivation for TDLS is bound (i.e., usedin the key derivation) to the affiliated non-AP STA MAC addresses of theTDLS peers. If the MAC address change is for an affiliated STA operatingin a TDLS link, the non-AP MLD 20 would negotiate the MAC address changewith both the TDLS peer and the AP MLD 12. After the MAC address changenegotiation has completed, the TDLS peers would negotiate a new TDLSpeer key. The key derivation protocol that would be invoked is definedand well known in the art. The MAC Address change messaging would be thesame.

The Category field may have a value of 30, for example, to indicateprivacy. The Category field may have a value of 10 if a Wireless NetworkManagement (WNM) Notification is used in other examples, as describedbelow. In such other examples, the non-AP MLD 20 transmits a WNMNotification Request (category field=10; action field=26; type=3 (MLOaddress update) and the AP MLD 12 transmits the WNM NotificationResponse (category=10; action field=26; type=3 (MLO address update)—theother message elements would be the same as the MAC address changenotification. The value options for the Address Update Action field are:a value of 0 to indicate that the frame is a Notification frame, a valueof 1 to indicate the frame is an Acknowledgement frame, and a value of 2to indicate that frame is a Confirm frame. The Dialog Token field mayhave a variable value. The dialog token is unique to a transaction andmay be the same for Request/Response/Confirm frames/messages in atransaction. The Number of Links field has a value of an integer thatrepresenting the number of links. The MLO Link field is described below.FIG. 7 is a diagram illustrating a MLO Link subfield format inaccordance with of the present disclosure. The Link ID subfield has avalue corresponding to the link identifier of the affiliated STA's linkwith a MAC address. The MAC Address subfield has a value correspondingto the requested MAC address. The MAC Address Change Notification framemay be used to request the MAC address change of more than oneaffiliated STA, in such cases, the MAC Address Change Notification frameincludes data for each of the affiliated STA with a requested MACaddress change.

FIG. 8 is a diagram illustrating a MAC Address Change Acknowledgementframe in accordance with the present disclosure. The Category field mayhave a value of 30, for example, to indicate privacy. The Address UpdateAction field has a value of 1 to indicate the frame is anAcknowledgement frame. The Dialog Token field is set to the value thatwas received in the MAC Address Change Notification frame. The Statusfield has a value corresponding to a Status code acknowledging thenotification, such as SUCCESS indicating a successful MAC address changeor FAIL indicating an unsuccessful MAC address change.

FIG. 9 is a diagram illustrating a MAC Address Change Confirmation framein accordance with the present disclosure. The Category field may have avalue of 30, for example, to indicate privacy. The Address Update Actionfield has a value of 2 to indicate that frame is a Confirm frame. TheDialog Token field may have is set to the value that was received in theMAC Address Change Acknowledgement frame. The Status field has a valuecorresponding to a Status code acknowledging the notification, such asSUCCESS indicating a successful MAC address change or FAIL indicating anunsuccessful MAC address change.

In accordance with the method 400, pairwise transient key securityassociation (PTKSA) establishment between the non-AP MLD 20 and the APMLD 12 is performed by the MLD entities. The PTKSA establishment isoutside the scope of the present disclosure and will not be addressfurther herein.

As an alternative to using a new action frame or an EAPoL data frame,the MAC address change may be performed over a TDLS link with the samemessaging. If the MAC address change is for an affiliated STA operatingin the TDLS link, the non-AP MLD 20 would negotiate the MAC addresschange with both the TDLS peer and the AP MLD. After the MAC addresschange negotiation has completed, the TDLS peers would negotiate a newTDLS peer key.

As a further alternative to defining a new action frame with a privacycategory, Wireless Network Management (WNM) Notificationrequest/response frames (i.e., notification/acknowledgement frames) maybe used in accordance with IEEE 802.11v. The payload of the notificationand acknowledgement frames would remain the same.

Referring now to FIGS. 10 and 11 , a method 450 of changing a MACaddress in accordance with a second embodiment of the present disclosurewill be described. FIG. 10 is flowchart of the method 500 in accordancewith the second embodiment of the present disclosure. FIG. 11 is amessage sequence diagram illustrating a message flow in accordance withthe second embodiment of the present disclosure. The solid lines in FIG.11 represent OTA messages whereas the broken lines in FIG. 11 presentinternal messages with an MLD. The frames (messages) sent between MLDscan be sent over any link. The method 450 is performed by the non-AP MLD20 and the AP MLD 12. At least parts of the method 400 may be carriedout by software executed by the non-AP MLD 20 and the AP MLD 12,affiliated STAs of the non-AP MLD 20, affiliated APs of the AP MLD 12,by the processors 104 and/or communication subsystems 110 thereof. Thesecond embodiment is similar to the first embodiment but differs in thatan affiliated STA 24 or 26 of the non-AP MLD 20, rather than the non-APMLD 20 itself, causes the MAC address change and notifies thecorresponding affiliated AP 14 or 16 of the AP MLD 12 through thecorresponding link. The method 450 appears the same or substantiallysimilar over-the-air but differs in the internal messages betweenelements (e.g., stations) of the MLDs 12, 20. The PTKSA is stillestablished between the non-AP MLD 20 and the AP MLD 12, thus thenotification frames originate at the affiliated STA 24 or 26, but aretransmitted as a link-specific notification to the correspondingaffiliated AP 14 or 16, as described below.

At operation 452, each affiliated STAs 24, 26 of the non-AP MLD 20monitors for a trigger to change its MAC addresses from one or morepredetermined triggers. The triggers may be time-based or event-based.For example, when the trigger is time-based, the trigger may be theexpiry of a predetermined amount of time, such as a predeterminedperiodic interval. The expiry of the predetermined amount of time may bemonitored by a timer, such as a countdown timer. The predeterminedamount of time may be a few minutes or as a little as a few seconds. Thepredetermined amount of time may be configured based on a privacysetting for the non-AP MLD 20. For another example, when the trigger isevent-based, the trigger may be the sending of a predetermined number offrames. The predetermined number of frames may be as little as a oneframe, so that the MAC address of the non-AP MLD 20 changes every frame.The smaller the time-based or event-based interval between changes inthe MAC address, the greater the privacy afforded.

At operation 454, one of the affiliated STAs 24, 26 of the non-AP MLD 20detects a trigger from the one or more predetermined triggers.

At operation 456, the one of the affiliated STAs 24, 26 of the non-APMLD 20 that detected the trigger generates a new MAC address for itselfand optionally one or more other affiliated STAs 24, 26 in response tothe detection of the trigger. It will be appreciated the affiliated STAcan generate a new MAC address for any one or more of the otheraffiliated STAs in the non-AP MLD 20, even though a trigger has not beendetected for those affiliated STAs. An affiliated non-AP STA can triggera MAC address change request for itself and other affiliated non-AP STAswithin a common non-AP MLD entity, or a MAC address change request of anaffiliated non-AP STA can trigger the non-AP MLD entity to trigger theother affiliated non-AP STAs to request their MAC addresses to change.In the present example, only the MAC address for one affiliated STA willbe changed for simplicity. There may be situations where not all the MACaddresses of all the affiliated STAs are changed or changed at the sametime.

At operation 458, the affiliated STA 24 or 26 of the non-AP MLD 20notifies its corresponding affiliated AP 14 or 16 of the AP MLD 12 thatit is requesting a MAC address change, for example, by sending a MACAddress Change Notification frame. The MAC Address Change Notificationframe is denoted in the message sequence diagram (FIG. 11 ) asMAC-ADDR-Change-Notif (AF_AP, AF_STA, newMACAddr), where AF_AP, AF_STAindicates AF_AP is the destination and AF_STA is the source of theframe/message and newMACAddr is the new MAC address. For multi-linkoperation, an affiliated STA can communicate with an affiliated AP butcannot do so directly. Instead, the affiliated STA sends the framethrough the non-AP MLD 20 to the AP MLD 12, which then sends the frameto the affiliated AP with the resulting path: Affiliated STA→non-APMLD→FRAME TRANSMISSION OTA→AP MLD→Affiliated AP.

At operation 460, the affiliated AP 14 or 16 receives the MAC AddressChange Notification frame and applies the MAC address change to updateits link mappings.

At operation 462, the affiliated AP 14 or 16 notifies the affiliated STA24 or 26 of the non-AP MLD 20 when the link mapping of the MAC addressfor the affiliated STA 24 or 26 has been successfully changed, forexample, by sending a MAC Address Change Acknowledgement frame. Forexample, the affiliated AP 14 or 16 may respond with a status ofSUCCESS, or may respond with an alternative status rather than SUCCESS,such as FAIL, when the MAC address change for the affiliated STA 24 or26 has not been applied. The MAC address may not succeed for severalreasons, for example, if the proposed MAC address is not suitable forthe AP MLD 12 or the affiliated AP 14 or 16 for some reason (e.g.,already in use for another device). The alternative status may cause theaffiliated STA 24 or 26 to re-try the MAC address change, in which caseoperations proceed to operation 456. The MAC Address ChangeAcknowledgement frame is denoted in the message sequence diagram (FIG.11 ) as MAC-ADDR-Change-ACK (SUCCESS), where Status is the status of theMAC address change, either SUCCESS or FAIL. The affiliated AP sends theframe through the AP MLD 12 to the non-AP MLD 20, which then sends theframe to the affiliated STA with the resulting path: Affiliated AP→APMLD→FRAME TRANSMISSION OTA→non-AP MLD→affiliated STA. As describedabove, the affiliated AP can alternatively respond with a Status codestopping the MAC address change or information about how the MAC addresschange should be performed.

At operation 464, the affiliated STA 24 or 26 applies the MAC addresschange in response to receiving the MAC Address Change Acknowledgementframe.

At operation 466, the affiliated STA 24 or 26 optionally notifies theaffiliated AP 14 or 16 that the MAC address for the non-STA AP has beensuccessfully changed, for example, by sending a MAC address ChangeConfirm frame to the affiliated AP 14 or 16. The affiliated STA sendsthe frame through the non-AP MLD 20 to the AP MLD 12, which then sendsthe frame to the affiliated AP with the resulting path: AffiliatedSTA→non-AP MLD→FRAME TRANSMISSION OTA→AP MLD→Affiliated AP. The MACAddress Change Confirm frame is denoted in the message sequence diagram(FIG. 11 ) as MAC-ADDR-Change-Confirm (AF-AP, AF-STA, Status), whereStatus is the status of the MAC address change, either SUCCESS or FAIL.The MAC address Change Confirm frame may be used to complete the MACaddress change and trigger the use of the new MAC address by theaffiliated AP 14 or 16 and the affiliated STA 24 or 26, and the AP MLD12 and non-AP MLD 20.

Although the foregoing embodiments related to a WLAN, it is complementedthat the teachings of the present disclosure may be extended to a WWANsuch as a cellular network.

The steps and/or operations in the flowcharts and drawings describedherein are for purposes of example only. There may be many variations tothese steps and/or operations without departing from the teachings ofthe present disclosure. For instance, the steps may be performed in adiffering order, or steps may be added, deleted, or modified, asappropriate.

General

The coding of software for carrying out the above-described methodsdescribed is within the scope of a person of ordinary skill in the arthaving regard to the present disclosure. Machine-readable codeexecutable by one or more processors of one or more respective devicesto perform the above-described method may be stored in amachine-readable storage medium such as the memory of the data manager.The terms “software” and “firmware” are interchangeable within thepresent disclosure and comprise any computer program stored in memoryfor execution by a processor, comprising Random Access Memory (RAM)memory, Read Only Memory (ROM) memory, EPROM memory, electrically EPROM(EEPROM) memory, and non-volatile RAM (NVRAM) memory. The above memorytypes are examples only, and are thus not limiting as to the types ofmemory usable for storage of a computer program.

All values and sub-ranges within disclosed ranges are also disclosed.Also, although the systems, devices and processes disclosed and shownherein may comprise a specific plurality of elements, the systems,devices and assemblies may be modified to comprise additional or fewerof such elements. Although several example embodiments are describedherein, modifications, adaptations, and other implementations arepossible. For example, substitutions, additions, or modifications may bemade to the elements illustrated in the drawings, and the examplemethods described herein may be modified by substituting, reordering, oradding steps to the disclosed methods.

Features from one or more of the above-described embodiments may beselected to create alternate embodiments comprised of a subcombinationof features which may not be explicitly described above. In addition,features from one or more of the above-described embodiments may beselected and combined to create alternate embodiments comprised of acombination of features which may not be explicitly described above.Features suitable for such combinations and subcombinations would bereadily apparent to persons skilled in the art upon review of thepresent disclosure as a whole.

In addition, numerous specific details are set forth to provide athorough understanding of the example embodiments described herein. Itwill, however, be understood by those of ordinary skill in the art thatthe example embodiments described herein may be practiced without thesespecific details. Furthermore, well-known methods, procedures, andelements have not been described in detail so as not to obscure theexample embodiments described herein. The subject matter describedherein and in the recited claims intends to cover and embrace allsuitable changes in technology.

Although the present disclosure is described at least in part in termsof methods, a person of ordinary skill in the art will understand thatthe present disclosure is also directed to the various elements forperforming at least some of the aspects and features of the describedmethods, be it by way of hardware, software or a combination thereof.Accordingly, the technical solution of the present disclosure may beembodied in a non-volatile or non-transitory machine-readable storagemedium (e.g., optical disk, flash memory, etc.) having stored thereonexecutable instructions tangibly stored thereon that enable a processingdevice to execute examples of the methods disclosed herein.

The term “database” may refer to either a body of data, a relationaldatabase management system (RDBMS), or to both. As used herein, adatabase may comprise any collection of data comprising hierarchicaldatabases, relational databases, flat file databases, object-relationaldatabases, object-oriented databases, and any other structuredcollection of records or data that is stored in a computer system. Theabove examples are example only, and thus are not intended to limit inany way the definition and/or meaning of the terms “processor” or“database”.

The present disclosure may be embodied in other specific forms withoutdeparting from the subject matter of the claims. The described exampleembodiments are to be considered in all respects as being onlyillustrative and not restrictive. The present disclosure intends tocover and embrace all suitable changes in technology. The scope of thepresent disclosure is, therefore, described by the appended claimsrather than by the foregoing description. The scope of the claims shouldnot be limited by the embodiments set forth in the examples, but shouldbe given the broadest interpretation consistent with the description asa whole.

The invention claimed is:
 1. A method of changing a medium accesscontrol (MAC) address of a wireless local area network (WLAN) affiliatednon-access point station (non-AP STA) of a non-AP multi-link device(MLD), the non-AP MLD comprising a plurality of affiliated non-AP STAs,the method comprising: generating a new MAC address for an affiliatednon-AP STA of the non-AP MLD; sending, by the non-AP MLD to an AP MLD, arequest to change the MAC address of the affiliated non-AP STA of thenon-AP MLD to the new MAC address; receiving, by the non-AP MLD from theAP MLD, an acknowledgement that the new MAC address for the affiliatednon-AP STA of the non-AP MLD has been successfully applied by the APMLD; and changing the MAC address for the affiliated non-AP STA of thenon-AP MLD to the new MAC address in response to the acknowledgment. 2.The method of claim 1, further comprising: sending, by the non-AP MLD tothe AP MLD, a confirmation that the MAC address of the affiliated non-APSTA of the non-AP MLD has been successfully changed.
 3. The method ofclaim 2, wherein the confirmation causes an affiliated AP of the AP MLDto use the new MAC address mapping for the affiliated non-AP STA of thenon-AP MLD.
 4. The method of claim 1, wherein generating the new MACaddress for the non-AP STA of the non-AP MLD is performed in response todetection of a trigger.
 5. The method of claim 4, wherein the trigger isan expiry of a predetermined amount of time since the MAC address of theaffiliated non-AP STA was set.
 6. The method of claim 4, wherein thetrigger is a sending of a predetermined number of frames since the MACaddress of the affiliated non-AP STA was set.
 7. The method of claim 6,wherein the predetermined number of frames is
 1. 8. The method of claim4, further comprising: monitoring for one or more triggers for changingthe MAC address for the affiliated non-AP STA of the non-AP MLD.
 9. Themethod of claim 8, wherein the monitoring, generating and changing isperformed by the non-AP MLD.
 10. The method of claim 8, wherein themonitoring, generating and changing is performed by the affiliatednon-AP STA of the non-AP MLD.
 11. The method of claim 1, wherein thegenerating, requesting and changing is performed by the non-AP MLD. 12.The method of claim 1, wherein the generating, requesting and changingis performed by the affiliated non-AP STA of the non-AP MLD.
 13. Themethod of claim 1, further comprising: sending data between theaffiliated non-AP STA of the non-AP MLD and an affiliated AP of the APMLD using the new MAC address.
 14. The method of claim 1, whereinprocessing of the request by the AP MLD causes the AP MLD to apply thenew MAC address change to a mapping of an affiliated AP of the AP MLD.15. A non-access point multi-link device (non-AP MLD), comprising: aprocessor; a communication subsystem coupled to the processor, whereinthe communication subsystem comprises a plurality of affiliated non-APstations (non-AP STAB); a memory coupled to the processor; wherein theprocessor is configured to: generate a new MAC address for an affiliatednon-AP STA of the non-AP MLD; send, by the non-AP MLD to an AP MLD, arequest to change the MAC address of the affiliated non-AP STA of thenon-AP MLD to the new MAC address; receive, by the non-AP MLD from theAP MLD, an acknowledgement that the new MAC address for the affiliatednon-AP STA of the non-AP MLD has been successfully applied by the APMLD; and change the MAC address for the affiliated non-AP STA of thenon-AP MLD to the new MAC address in response to the acknowledgment. 16.The non-AP MLD of claim 15, wherein the processor is further configuredto: send, by the non-AP MLD to the AP MLD, a confirmation that the MACaddress of the affiliated non-AP STA of the non-AP MLD has beensuccessfully changed.
 17. The non-AP MLD of claim 16, wherein theconfirmation causes an affiliated AP of the AP MLD to use the new MACaddress for the affiliated non-AP STA of the non-AP MLD.
 18. The non-APMLD of claim 15, wherein generating the new MAC address for the non-APSTA of the non-AP MLD is performed in response to detection of atrigger.
 19. The non-AP MLD of claim 15, wherein processing of therequest by the AP MLD causes the AP MLD to apply the new MAC addresschange to a mapping of an affiliated AP of the AP MLD.
 20. Anon-transitory machine-readable storage medium having tangibly storedthereon executable instructions for execution by a processor of annon-access point (AP) multi-link device (MLD), the non-AP MLD comprisinga processor and a communication subsystem coupled to the processor, thenon-AP MLD comprising a plurality of affiliated non-AP stations (STAs),wherein the executable instructions, in response to execution by theprocessor, cause the non-AP MLD to: generate a new MAC address for anaffiliated non-AP STA of the non-AP MLD; send, by the non-AP MLD to anAP MLD, a request to change the MAC address of the affiliated non-AP STAof the non-AP MLD to the new MAC address; receive, by the non-AP MLDfrom the AP MLD, an acknowledgement that the new MAC address for theaffiliated non-AP STA of the non-AP MLD has been successfully applied bythe AP MLD; and change the MAC address for the affiliated non-AP STA ofthe non-AP MLD to the new MAC address in response to the acknowledgment.